1. Field of the Invention
The present invention relates to a display apparatus and a display method for display of a focus state at the time of image picking-up (photography).
2. Description of the Related Art
For the purpose of clearly displaying a focus state, Japanese Laid-open Patent Publication No. 2002-196225 discloses a technique for detecting a focus state of a picked-up image in a high spatial frequency range and for displaying on the picked-up image the degree of the focus state using a color difference.
Also there are many proposals to display a focus state not on a picked-up image but on a separate member such as for example an LED.
With the apparatus proposed in Japanese Laid-open Patent Publication No. 2002-196225, it is possible to determine based on color an image part which is the best in the focus state. However, even when the best focus state cannot be attained by a focus operation, the direction in which the next focus operation should be made is not clearly indicated, which poses a problem.
With a technique to determine a color based on the magnitude of a contrast value, if the object is low in contrast, a color representative of an optimum focus state sometimes does not appear on a screen, making it difficult to find an optimum focus state.
Especially with a focus operation using buttons, switches, etc., it is not possible, unlike in a focus operation using a manual focus ring, etc., to locate an optimum position while changing the focus position back and forth. As a result, a tendency of an in-focus peak position being difficult to find becomes noticeable in a fine focus adjustment.
In practical photography, an aperture is usually controlled in consideration of the depth of field and thus whether or not the in-focus position is within the depth of field is sometimes more important than the in-focus peak position. However, means for solving that problem is not disclosed in Japanese Laid-open Patent Publication No. 2002-196225.